Question

A ball attached at the end of a string revolving in a horizontal circle of radius,R,at whirle a constant speed,v.The tension in the string is F.What is the force needed to increase the speed by 50%?

Answer 1

$F=m\frac{v^2}{R}$

When the speed is increased

$F_i=m\frac{(1.5v)^2}{R}=2.25\cdot m\frac{v^2}{R}=2.25F$

$F_i=2.25F$ . Answer